Lager made with the 133-year-old yeast that forever changed beer is surprisingly tasty

For a long part of humanity's history, beer was more than an
after-work or weekend beverage. In many years and in many
cultures, going
back to at least the construction of the pyramids of Egypt,
daily rations of beer helped fuel workers throughout their
days.

More recently, factory workers used those malted rations to
get through their labor.

And while the taste and alcohol content of many of these beers
varied greatly, it turns out that by the end of the 19th century,
at least some factory workers were downing a brew that would
still be considered surprisingly tasty by today's standards.

We know this because near the end of the 2016, Business
Insider had the chance to visit Brooklyn Brewery for an
event hosted with the Danish brewery Carlsberg to try a beer made
with 133-year-old yeast that had been extracted from one of the
first bottles of lager ever brewed with purified lager yeast.

This wasn't just a copy of a beer dating back to those days, it
actually used an ancient ingredient. That still-living yeast was
taken from one of those more than 100-year-old bottles and was
used to create a fresh batch of beer according to the original
specifications of 19th century brewers: the
Carlsberg Rebrew.

A dark lager with a rich brown color and a taste that resembles a
good bread, complex without being too heavy or malty, the Rebrew
was more interesting and flavorful than many modern lagers.

"Elegant rather than dense, at 5.8% abv it’s in the style of a
Munich dark lager, the style of the day, the dark color being
driven by the specially kilned malts," Susanna Forbes writes,
describing the same beer for Imbibe Magazine. "The flavors of
rich toffee are accompanied by some residual sweetness."

Carlsberg's
Bjarke Bundgaard showed this copy of the 19th century brewing
records that were used to create the Rebrew.Kevin Loria/Business Insider

Perhaps most importantly, it's a very drinkable brew — essential
since factory workers at the end of the 1800s drank quite a lot
of it.

Every worker got four liters of beer as their daily ration at the
time, according to Bjarke Bundgaard, a beer historian for
Carlsberg, the Danish brewery behind Rebrew.

But it was only in the 19th century, relatively recently in the
history of beer, that scientists isolated yeast itself,
understanding the full role that these tiny creatures played.

Different types of yeast make different beers. While
some produce consistent and predictable results, others can
be incredibly unpredictable.

Kevin Loria/Business Insider

In the latter half of the 19th century, a number of scientists —
pioneers of microbiology — were starting to crack the
mysteries of fermention, realizing that yeast was responsible for
the seemingly magical transformation of water into beer. Louis
Pasteur was one of those researchers and is frequently credited
with revealing many of the mysteries of fermentation, but it was
in 1883 that
Emil Christian Hansen, a researcher at the
Carlsberg Laboratory (Carlsberg conducts scientific research
alongside their beer-making operation), actually managed to
isolate the yeast that was considered the key to lager
production.

Lager had skyrocketed in popularity at the time. But many
batches of the cold-fermenting beer would spoil, contaminated by
wild yeast. In order to prevent that spoilage, researchers
realized they'd have to identify the species that made the
perfect lager, using that and only that for fermentation. That
was the inspiration for Hansen's work, and after the discovery,
the brewery reportedly shared that special lager yeast with the
rest of the industry.

There are different varieties of yeast that can be used for
lager, but that original species, Saccharomyces
pastorianus, was the main one that most future lagers would
use. And according to scientists at Carlsberg, the genetic
sequence of the specimen they took from those old bottles for the
Rebrew project is essentially a perfect match for the original
samples in their gene bank.

S. pastorianus is the name for that yeast that has won
precedence today, a name in honor of Pasteur. But Hansen had
called the yeast by another name, one that was considered a
synonym for its current moniker for some time, Saccharomyces
carlsbergensis.

And at Brooklyn Brewery, where Business Insider had the chance to
taste the Rebrew, brewmaster Garrett Oliver claimed that some
circles still go by that name.